In recent years, color filters have been one of the essential components for devices such as CCD image sensors, CMOS image sensors, liquid crystal displays, and organic EL displays.
Generally, in order to protect a color filter and to planarize the surface unevenness of the color filter, a transparent resin film such as a protection film and a planarization film is formed as the upper layer of the color filter. In order to improve adhesion between the color filter and a base substrate and to planarize the unevenness due to existence of, for example, a circuit wiring part, a light-shielding film, and an inner lens, a transparent resin film is also formed as the under layer of the color filter. A composition for forming such transparent resin films is described in, for example, Patent Document 1 to Patent Document 4.
For forming the color filter, for example, color resists of three colors of red, green and blue that contain pigments or dyes are generally used. A method for forming the color filter containing the color resists of three colors includes applying a color resist of a first color, exposing the applied color resist to light, and developing and heating the exposed color resist to form a color resist pattern of the first color. Thereafter, the method includes forming the color resist patterns of a second color and a third color in a similar manner to the resist pattern of the first color to form a color filter.
In such a method for forming a color filter, it is important to reduce generation of a color resist residue at the time of the color resist pattern formation in order to reduce deterioration in color reproducibility of the color filter and decrease in the yield of devices including the color filter.
When the color filter is formed on the transparent resin film, properties of reducing generation of the color resist residue as described above are required to the transparent resin film. When the color resist pattern is formed on a conventional transparent resin film, however, the properties of reducing generation of the color resist residue are not sufficiently satisfied.